O'Donnell, C. (2000). Science and Technology Concepts for Middle Schools; Catastrophic Events. Burlington, North Carolina: Carolina Biological Supply Company.
Lesson 16 - Convection in the Mantle
Part 2:
National Science Education Standards, Earth Science, Grades 5-8 The solid earth is layered with a lithosphere; hot, convecting mantle; and dense, metallic core.
1. What does this standard mean?
Earth is composed of various layers of different kinds of materials with varying densities and temperatures.
The crust is earth's outermost layer and is the coolest and least dense layer. It is made of rock.
The mantle is found beneath the crust and is composed of rock that is denser than the rock in the crust. It has two layers.
The top layer of the mantle is rigid and cooler than the lower layer of the mantle.
This rigid part of the mantle, combined with the crust, is refered to as the lithosphere.
The lower layer of the mantle is hot and can flow. It is called the asthenosphere.
The flow of materials in the lower mantle is due to convection currents.
A convection current is a circulating flow that occurs when there is uneven heating.
In the mantle, liquid close to the core heats and becomes lighter, causing it to rise. As it rises, cold liquid moves in to replace it and is also heated, causing it to rise. As the heated air rises, it cools and will eventually sink to be heated again. This movement is a continuous cycle.
Below the asthenosphere is the innermost layer of earth called the core.
The core is made up of a liquid outer layer made of iron and a solid inner layer made of iron and nickel. The core is extremely hot.
2. What prior knowledge do students need to understand the standard?
That density is a measure of mass per unit volume.
That less dense materials will float above more dense materials.
That hot material rises because it is less dense than cold material.
3. What misconceptions might students have around the topics contained in the standard?
That the "liquid" portion of the mantle and core is like water.
That the flow in the mantle, is like the flow of water in a river.
That convection currents are happening very rapidly.
Grade Eight (Ages 13-15)
O'Donnell, C. (2000). Science and Technology Concepts for Middle Schools; Catastrophic Events. Burlington, North Carolina: Carolina Biological Supply Company.
Lesson 16 - Convection in the Mantle
Part 2:
National Science Education Standards, Earth Science, Grades 5-8
The solid earth is layered with a lithosphere; hot, convecting mantle; and dense, metallic core.
1. What does this standard mean?
2. What prior knowledge do students need to understand the standard?
3. What misconceptions might students have around the topics contained in the standard?
Parts 3 & 4: